Joan Robinson was a prominent economist known for her contributions to Keynesian economics and her critique of classical economic theories. She emphasized the importance of imperfect competition and argued that markets do not always reach equilibrium. Her work highlighted how firms have pricing power, which can lead to monopolistic practices and affect overall economic efficiency. Robinson also introduced the concept of monopsony, where a single buyer controls the market, impacting wages and employment. Her theories challenged traditional views on labor markets and income distribution, advocating for a more nuanced understanding of economic dynamics and the role of power in shaping market outcomes.